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169
Adaptive Nonlinear Finite Elements for Deformable Body Simulation Using Dynamic Progressive Meshes
 Computer Graphics Forum
, 2001
"... Realistic behavior of deformable objects is essential for many applications such as simulation for surgical training. Existing techniques of deformable modeling for real time simulation have either used approximate methods that are not physically accurate or linear methods that do not produce reas ..."
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Cited by 85 (3 self)
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Realistic behavior of deformable objects is essential for many applications such as simulation for surgical training. Existing techniques of deformable modeling for real time simulation have either used approximate methods that are not physically accurate or linear methods that do not produce reasonable global behavior. Nonlinear finite element methods (FEM) are globally accurate, but conventional FEM is not real time. In this paper, we apply nonlinear FEM using mass lumping to produce a diagonal mass matrix that allows real time computation. Adaptive meshing is necessary to provide sufficient detail where required while minimizing unnecessary computation. We propose a scheme for mesh adaptation based on an extension of the progressive mesh concept, which we call dynamic progressive meshes. 1.
Removing excess topology from isosurfaces
 ACM Trans. Graph
, 2004
"... Many highresolution surfaces are created through isosurface extraction from volumetric representations, obtained by 3D photography, CT, or MRI. Noise inherent in the acquisition process can lead to geometrical and topological errors. Reducing geometrical errors during reconstruction is well studie ..."
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Cited by 81 (1 self)
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Many highresolution surfaces are created through isosurface extraction from volumetric representations, obtained by 3D photography, CT, or MRI. Noise inherent in the acquisition process can lead to geometrical and topological errors. Reducing geometrical errors during reconstruction is well studied. However, isosurfaces often contain many topological errors in the form of tiny handles. These nearly invisible artifacts hinder subsequent operations like mesh simplification, remeshing, and parametrization. In this paper we present an efficient method for removing handles in an isosurface. Our algorithm makes an axisaligned sweep through the volume to locate handles, compute their sizes, and selectively remove them. The algorithm is designed for outofcore execution. It finds the handles by incrementally constructing and analyzing a surface Reeb graph. The size of a handle is measured by a short surface loop that breaks it. Handles are removed robustly by modifying the volume rather than attempting “mesh surgery. ” Finally, the volumetric modifications are spatially localized to preserve geometrical detail. We demonstrate topology simplification on several complex models, and show its benefit for subsequent surface processing.
A topological hierarchy for functions on triangulated surfaces.
 IEEE Transactions on Visualization and Computer Graphics,
, 2004
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Progressive lossless compression of arbitrary simplicial complexes
 ACM Trans. Graphics (Proc. ACM SIGGRAPH 2002
, 2002
"... Efficient algorithms for compressing geometric data have been widely developed in the recent years, but they are mainly designed for closed polyhedral surfaces which are manifold or “nearly manifold”. We propose here a progressive geometry compression scheme which can handle manifold models as well ..."
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Cited by 76 (0 self)
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Efficient algorithms for compressing geometric data have been widely developed in the recent years, but they are mainly designed for closed polyhedral surfaces which are manifold or “nearly manifold”. We propose here a progressive geometry compression scheme which can handle manifold models as well as “triangle soups ” and 3D tetrahedral meshes. The method is lossless when the decompression is complete which is extremely important in some domains such as medical or finite element. While most existing methods enumerate the vertices of the mesh in an order depending on the connectivity, we use a kdtree technique [8] which does not depend on the connectivity. Then we compute a compatible sequence of meshes which can be encoded using edge expansion [14] and vertex split [24]. 1 The main contributions of this paper are: the idea of using the kdtree encoding of the geometry to drive the construction of a sequence of meshes, an improved coding of the edge expansion and vertex split since the vertices to split are implicitly defined, a prediction scheme which reduces the code for simplices incident to the split vertex, and a new generalization of the edge expansion operation to tetrahedral meshes. 1
Approximate NView Stereo
 in Proc. European Conf. on Computer Vision
, 2000
"... . This paper introduces a new multiview reconstruction problem called approximate Nview stereo. The goal of this problem is to recover a oneparameter family of volumes that are increasingly tighter supersets of an unknown, arbitrarilyshaped 3D scene. By studying 3D shapes that reproduce the in ..."
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Cited by 72 (5 self)
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. This paper introduces a new multiview reconstruction problem called approximate Nview stereo. The goal of this problem is to recover a oneparameter family of volumes that are increasingly tighter supersets of an unknown, arbitrarilyshaped 3D scene. By studying 3D shapes that reproduce the input photographs up to a special image transformation called a shuffle transformation,we prove that (1) these shapes can be organized hierarchically into nested supersets of the scene, and (2) they can be computed using a simple algorithm called Approximate Space Carving that is provablycorrect for arbitrary discrete scenes (i.e., for unknown, arbitrarilyshaped Lambertian scenes that are defined by a finite set of voxels and are viewed from N arbitrarilydistributed viewpoints inside or around them). The approach is specifically designed to attack practical reconstruction problems, including (1) recovering shape from images with inaccurate calibration information, and (2) building ...
Generalized ViewDependent Simplification
 EUROGRAPHICS '99 / P. BRUNET AND R. SCOPIGNO
, 1999
"... We propose a technique for performing viewdependent geometry and topology simplifications for levelofdetailbased renderings of large models. The algorithm proceeds by preprocessing the input dataset into a binary tree, the viewdependence tree of general vertexpair collapses. A subset of the ..."
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Cited by 70 (8 self)
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We propose a technique for performing viewdependent geometry and topology simplifications for levelofdetailbased renderings of large models. The algorithm proceeds by preprocessing the input dataset into a binary tree, the viewdependence tree of general vertexpair collapses. A subset of the Delaunay edges is used to limit the number of vertex pairs considered for topology simplification. Dependencies to avoid mesh foldovers in manifold regions of the input object are stored in the viewdependence tree in an implicit fashion. We have observed that this not only reduces the space requirements by a factor of two, it also highly localizes the memory accesses at run time. The viewdependence tree is used at run time to generate the triangles for display. We also propose a cubicsplinebased distance metric that can be used to unify the geometry and topology simplifications by considering the vertex positions and normals in an integrated manner.
Single resolution compression of arbitrary triangular meshes with properties
 In Data Compression Conference’99 Conference Proceedings
, 1999
"... Polygonal meshes have been used as the primary geometric model representation for networked gaming and for complex interactive design in manufacturing. Accurate polygonal mesh approximation of a surface with sharp features (holes, highly varying curvatures) requires extremely large number of triangl ..."
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Cited by 66 (3 self)
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Polygonal meshes have been used as the primary geometric model representation for networked gaming and for complex interactive design in manufacturing. Accurate polygonal mesh approximation of a surface with sharp features (holes, highly varying curvatures) requires extremely large number of triangles. Transmission of such large triangle meshes is
External memory viewdependent simplification
 IN PROCEEDINGS EUROGRAPHICS (2000
, 2004
"... In this paper, we propose a novel externalmemory algorithm to support viewdependent simplification for datasets much larger than main memory. In the preprocessing phase, we use a new spanned submeshes simplification technique to build viewdependence trees I/Oefficiently, which preserves the cor ..."
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Cited by 52 (5 self)
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In this paper, we propose a novel externalmemory algorithm to support viewdependent simplification for datasets much larger than main memory. In the preprocessing phase, we use a new spanned submeshes simplification technique to build viewdependence trees I/Oefficiently, which preserves the correct edge collapsing order and thus assures the runtime image quality. We further process the resulting viewdependence trees to build the metanode trees, which can facilitate the runtime levelofdetail rendering and is kept in disk. During runtime navigation, we keep in main memory only the portions of the metanode trees that are necessary to render the current level of details, plus some prefetched portions that are likely to be needed in the near future. The prefetching prediction takes advantage of the nature of the runtime traversal of the metanode trees, and is both simple and accurate. We also employ the implicit dependencies for preventing incorrect foldovers, as well as mainmemory buffer management and parallel processes scheme to separate the disk accesses from the navigation operations, all in an integrated manner. The experiments show that our approach scales well with respect to the main memory size available, with encouraging preprocessing and runtime rendering speeds and without sacrificing the image quality.
Progressive coding of 3D graphic models
 Proc. IEEE 86 (6
, 1998
"... Based on stateoftheart graphicsimplification techniques and progressive imagecoding schemes, we propose a new hierarchical threedimensional graphiccompression scheme in this research. This scheme progressively compresses an arbitrary polygonal mesh into a single bitstream. Along the encoding ..."
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Cited by 49 (16 self)
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Based on stateoftheart graphicsimplification techniques and progressive imagecoding schemes, we propose a new hierarchical threedimensional graphiccompression scheme in this research. This scheme progressively compresses an arbitrary polygonal mesh into a single bitstream. Along the encoding process, every output bit contributes to the reduction of coding distortion, and the contribution of bits decreases according to their order of position in the bitstream. At the receiver end, the decoder can stop at any point while giving a reconstruction of the original model with the best ratedistortion tradeoff. A series of models of continuous varying resolution can thus be constructed from the single bitstream. This property, which is referred to as the embedding property since the coding of a coarser model is embedded in the coding of a finer model, can be widely used in robust error control, progressive transmission and display, levelofdetail control, etc. It is demonstrated by experiments that an acceptable quality level can be achieved at a compression ratio of 20 to 1 for several test graphic models. Keywords—Embedded codecs, graphic coding, graphic simplification, progressive coding. I.